We look at the division of 663999 by 25 
We want to divide 663999 by 25.

Let's proceed to step 1:
When dividing 6 by 25, we get 0 with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 25

On to step 2:
66 divided by 25 is 2 with a remainder of 16.
Put 2 as the next digit of the answer. 
Result so far: 2.0
The remainder is 16 after subtracting 50 from 66.
Grab the next digit (3) from the dividend, add it to 16, then carry on: 163 / 25

On to step 3:
25 goes into 163 6 times with a remainder of 13.
Use 6 as the next digit of our solution. 
Result so far: 26.0
Subtract 150 from 163 to get 13.
Append the next digit (9) from the dividend to 13 and continue with: 139 / 25

On to step 4:
If we divide 139 by 25, we get 5 and a remainder of 14.
Put 5 as the next digit of the answer. 
Result so far: 265.0
The remainder is 14 after subtracting 125 from 139.
Grab the next digit (9) from the dividend, add it to 14, then carry on: 149 / 25

Let's proceed to step 5:
149 divided by 25 is 5 with a remainder of 24.
Use 5 as the next digit of our solution. 
Result so far: 2655.0
Subtract 125 from 149 to get 24.
Append the next digit (9) from the dividend to 24 and continue with: 249 / 25

Going ahead to step 6:
25 goes into 249 9 times with a remainder of 24.
Put 9 as the next digit of the answer. 
Result so far: 26559.0
Subtract 225 from 249 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 7:
The number 25 fits into 240 9 times, leaving a remainder of 15.
Use 9 as the next digit of our solution. 
Result so far: 26559.9
Deduct 225 from 240 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 8:
25 goes into 150 6 times with a remainder of 0.
Write down 6 as next digit of the result. 
Result so far: 26559.96
Subtracting 150 from 150 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 9:
When dividing 0 by 25, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 26559.96
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 10:
If we divide 0 by 25, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 26559.96
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 26559.96 with a remainder of 0.0.